A recording tape cartridge such as a video tape cartridge or an audio tape cartridge of the digital type is provided with a movable lid on the front portion of the cartridge case and is adapted to be mounted on a recording/reproducing apparatus (referred to as a tape player hereinafter) in such a manner that the video tape cartridge is manually inserted in the housing of the tape player in a horizontally laid attitude and is moved downward toward the loading postion with the lid of the tape cartridge opened during the downward movement. In actual use, it is required that the video tape must be so positioned at the loading position that the drive shaft insertion holes of the hubs of the video tape cartridge can be correctly engaged with the drive shafts of the tape player. For this purpose, the tape cartridge must be precisely positioned at the end of the horizontal movement of the manual insertion of the cartridge. In order to regulate the position of the video tape cartridge, conventionally there is provided a positioning member in the tape player which is adapted to contact a part of the front end face of the case of the tape cartridge through an opening defined on the front plate of the lid.
In general, in the positioning arrangement, it is preferred to make the contact area of the positioning member of the tape player as large as possible so as to ensure the positioning of the cartridge. For achieving this, it is necessary to expand the opening of the lid for allowing the passage of the enlarged positioning member of the tape player. However, a large opening on the front lid decrease the mechanical strength of the front lid. In addition since the conventional positioning member of the tape player is adapted to engage the front portion of the tape cartridge near the recording tape, the tape may be easily harmed due to undesired contact with the enlarged positioning member. In view of the condition as described above, the opening of the lid in fact can not be expanded. It has be considered to open the lid member as large as possible in a range so as not to decrease the mechanical strength of the lid member so as to allow the positioning member of the tape player to contact the front portion of the cartridge through the opening for positioning. By this arrangement, the above mentioned problem may be solved. However, on the contrary, there occurs the problem that since the size of the positioning member must be determined corresponding to the size of the opening, when the tape cartridge is mounted in the tape player with a sudden force, the tape cartridge may ride over the positioning member, whereby the tape cartridge will not be positioned in the correct position.
Since the conventional positioning mechanism uses such a construction as to provide the opening in the front lid of the cartridge for receiving the positioning member, there are many restrictions and therefore the conventional positioning mechanism used in the tape cartridge is not able to comply with the requirement of the variation of the tape cartridges.